# physics

posted by .

A 1.0 kg red superball moving at 5.0 m/s collides head-on with stationary blue superball of mass 4.0 kg in an elastic collision. What are the final velocities of the two superballs after the collision?

• physics -

In an elastic collision, both kinetic energy and momentum are conserved.
Let
m1=mass of red superball=1
m2=mass of blue superball=4
v11=initial velocity of red ball=5
v12=final velocity of red ball
v21=initial velocity of blue ball=0
v22=final velocity of blue ball

For conservation of energy,
(m1/2)v11² + (m2/2)v12² = (m1/2)v12² + (m2/2)v22².....(1)

For conservation of momentum,
(m1/2)v11 + (m2/2)v12 = (m1/2)v12 + (m2/2)v22 .......(2)

The only unknowns are v12 and v22. With the two equations, it is therefore possible to solve for the unknowns.

From (2), we express v12 in terms of the other unknown and the known constants, thus:
v12 = -(m2*v22-m2*v21-m1*v11)/m1

Substitute v12 into equation 1 will leave v22 as the only unknown.

Solving for v12 and v22, you should get
V12=-3 m/s, and v22=2 m/s.

Check that they satisfy the considerations of energy and momentum.

• physic-corr -

Note the following typographical corrections.

For conservation of energy,
(m1/2)v11² + (m2/2)v21² = (m1/2)v12² + (m2/2)v22².....(1)

For conservation of momentum,
m1 v11 + m2 v21 = m1 v12 + m2 v22 .......(2)
That is to say there is no need to divide the momentum by 2. Although this alone will not affect the final results.

• physics -

tried solving it got different final results

## Similar Questions

1. ### Physics

A 6.00 kg ball (ball 1), moving to the right at a velocity of +1.00 m/s on a frictionless table, collides head-on with a stationary 7.50 kg ball (ball 2). Find the final velocities of the balls if the collision is as specified below. …
2. ### physics

Ball 1, with a mass of 100g and traveling at 12 m/s , collides head on with ball 2, which has a mass of 340g and is initially at rest. What are the final velocities of each ball if the collision is perfectly elastic?
3. ### physics

Ball 1, with a mass of 180 g and traveling at 18 m/s, collides head on with ball 2, which has a mass of 370 g and is initially at rest (a) What are the final velocities of each ball if the collision is perfectly elastic?

A 5.00 kg ball (ball 1), moving to the right at a velocity of +4.00 m/s on a frictionless table, collides head-on with a stationary 7.60 kg ball (ball 2). Find the final velocities of the balls if the collision is as specified below. …

A 5.00 kg ball (ball 1), moving to the right at a velocity of +4.00 m/s on a frictionless table, collides head-on with a stationary 7.60 kg ball (ball 2). Find the final velocities of the balls if the collision is as specified below. …

A 5.00 kg ball (ball 1), moving to the right at a velocity of +4.00 m/s on a frictionless table, collides head-on with a stationary 7.60 kg ball (ball 2). Find the final velocities of the balls if the collision is as specified below. …
7. ### physics

A proton that has a mass m and is moving at 250 m/s in the + direction undergoes a head-on elastic collision with a stationary oxygen nucleus of mass 16m. Find the velocities of the proton and the carbon nucleus after the collision
8. ### physics

A 2.20-kg ball, moving to the right at a velocity of +1.27 m/s on a frictionless table, collides head-on with a stationary 7.20-kg ball. Find the final velocities of (a) the 2.20-kg ball and of (b) the 7.20-kg ball if the collision …
9. ### Physics

1. A stationary curling stone is struck in a glancing collision by a second curling stone of equal mass. If the first stone moves away at a velocity of 0.92 m/s [N71oW] and the second stone moves away at a velocity of 1.25 m/s [N44oE], …
10. ### physics

a helium nuclide of mass M1 moving with initial velocity V is incident on a stationary of mass M1. After collision M1 was deflected through an angle x and M2 an angle y. If the velocities of the nuclides after collision were V1 and …

More Similar Questions